Electrical apparatus



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fi'orneg I Patented Aug. 13, 1946 ELECTRICAL APPARATUS Gerson E. Wald,Far Rockaway, N. Y., assignor to Bendix Aviation Corporation, Bendix, N.J., a

corporation of Delaware Application June 9, 1943, Serial No. 490,196

2 Claims.

This invention relates to electrical apparatus, and particularly to theapplication of indicating means to electrical circuits, to indicate thecondition of fuses controlling flow of current there- An object of theinvention is to indicate electrically the condition of fuses employed inelectric circuits.

Another object is to provide an electrical fuse of novel construction,which novel construction permits the fuse to function as the means foractuating electrical means to indicate when the fuse has blown.

Another object is to provide means to indicate when a fuse has beenremoved from the circuit to which it is applied; the same means alsofunctioning to indicate a blown fuse.

These and other objects of the invention will become apparent frominspection of the following specification when read with reference tothe accompanying drawings wherein is illustrated the preferredembodiment of the invention. It is to be expressly understood, however,that the drawings are for the purpose of illustration only, and are notdesigned as a definition of the limits of the invention, reference beinghad to the appended claims for this purpose.

In the drawings:

Fig. 1 is a view partly in section, partly in elevation, and partlyschematic, of apparatus embodying the invention;

Fig. 2 is a sectional view along line 2'2 of Fig. 1;

Fig. 3 is a view similar to Fig. 2 but showing the relative positions ofthe parts when a fuse has blown;

Fig. 4 is a sectional view along line 44 of Fig. 2 and also includes ashowing of the fuse holder detached from the fuse board;

Fig. 5 is a perspective view of the parts shown in Fig. 4;

Fig. 6 is another perspective view of the fuse holder;

Fig. '7 is a perspective View of the fuse clip assembly for two fuses;

Fig. 8 is a view in perspective of a second embodiment of the invention;

Fig. 9 is a schematic representation of the electrical connectionsinvolved when the form of the invention shown in Fig. 8 is employed;

Fig. 10 is a View similar to Fig. 9 but showing the circuit closed bythe blowing of one fuse;

Fig. 11 is a View similar to Figs. 9 and 10 but showing the circuitclosed by the removal of one or more fuses from their operativepositions on the fuse board; and

Fig. 12 is a schematic showing of a modified circuit wherein there is asignal element individual to each fuse.

In Figs. 1 to 7 reference characters 16, ll, i8 and I9 designate fusesadapted to be held in electrical contact with fuse clip fingers, thosfor fuse I9 being numbered 2|, 22, 23 and 24. As shown in Figs. 2 and 3,each fuse is of novel construction, including an apertured upper endreceiving a plunger of the series shown at 26, 27, 28 and 29 in Fig. 1,said plunger 29 being engaged by the head 3! of a fusible wire rod 32extending centrally-through the fuse l9 and secured at the base of thefuse, as shown at 33. A cap 31 is urged upwardly from spring seat 38, bya spring 39, and when the fusible wire 32 breaks, due to excessiveelectrical heating, the spring 39 snaps the cap 37, wire head 31 andplunger 29 upwardly (see Fi 3) thereby tilting the plunger carryingstrip 4! in such a direction as to actuate the plunger 42 (Fig. 1) ofthe microswitch 43-the said micro-switch 43 being of any snap-actiontype well-known in the art, as, for example, the type shown in McGallPatent No. 1,960,020, granted May 22, 1934.

A flexible metallic strip 46 is anchored at one end to the switchhousing, as in conventional micro-switch construction, and its other endcarries the non-conducting strip 4| the whole being suspended from theswitch housing which in turn is screwed to the fuse panel 48, or abracket thereon.

Fuse holders 5| and 52 are shown as carrying the fuses IE to l9, therebeing two fuses for each holder. Each holder has a ledge 54 and acentral boss 53 apertured to receive the fuses, and also recessed toreceive the conical head 55 of the fuse block 56, the latter beingfastened to panel 48. These parts 53, 55 and 54 cooperate to positionand retain the fuses in proper relation to the fuse clips.

From the foregoing disclosure, it is apparent that, should any one ofthe four fuses become blown, for instance fuse l9, its plunger 3i willbe moved up under the influence of spring 39 into the position shown inFig. 3 which through plunger 29 rocks insulated strip 4| upwardly. This,through plunger 42 closes the micro-switch 43 which completes thecircuit of lamp 44 which gives a visible signal showing that one or moreof the four fuses has blown. The invention also may assume a form inwhich removal of any of the fuses from the holding clips is alsooperable 3 to energize the indicator circuit. This mcdification of theinvention will now be described.

In Figs. 8 to 11 each fuse block is equipped with levers (see levers 6l, 62 in Fig. 8) ivoted to the sides of the block, as at 63 and E4, andurged downward by springs 66, 61, the latter being anchored to the blockat ll, '52. Each lever is of insulating material, but each carries ametal bar 73, M, engageable with the fuse clip tips of the adjacent fuseclip (as indicated at 8!, 82, 83 and 64 in Fig. 11) when urged downwardby springs '56, 6'! in the absence of the fuses. the fuses willautomatically thrustthe levers M, 62 backwardly due to the resultingphysical" interference between central bulge 553 on the one hand and thesloping edges of levers ill, (52 on the other, thus causing metal barsl3, id to move back and up, into the relative positions, with. respectto fuse clip tips, that are indicated in Fig. 9. In the Fig. 11positions of metal bars l3, '14, parallel circuits are closed toenergize signal lamp 9! (or separate signal lamps 93, as, in thearrangement of Fig. 123 while in Fig. 9' thelamp is extinguished, due tothe open condition ofboth branches of the circuit.

In the eventof a blown fuse, as at I? in Fig. 10, the fusible wire head3! (as in Figs. 2'and 3) will be pushed up into contact with the. bar13', thus closing the circuit to light the lamp 91, in lieu of themicro-switch ofFig. 1v

What'is claimed is:

1. In an electrical apparatus, a plurality of fuses operable to limitthe current flow in severalcircuits, each fuse comprising a fusibleelement and means for axially displacing one end of Insertion of 4 saidelement in response to fusion thereof, an auxiliary circuit containingan electrically energized signal device, a normally open switch disposedin operative relationship to said fuses and operable to control saidcircuit, and means coacting with said switch and the fusible elements ofall of said fuses for causing said switch to close and energize saidsignal device when any of said fusible elements are displaced axially,said last named means comprising an arm mounted for rocking movement andcarrying a plurality of membersaligned with. and engageable by any oneof the fusible elements of. said fuses.

2. In an electrical apparatus, a plurality of fuses operable to limitthe current flow in several circuits, each fuse comprising a fusibleelement and-means for axially displacing one end of said element inresponse to fusion thereof, an auxiliary circuit containing anelectrically energized signal device, a normally open switch disposed inoperative relationship to saidfuses and operable to control'saidcircuit, and means'coa'cting with saidswitch and the" fusibleel'ements'of all of said fuses for causing said switch to close and energiz saidsignal device whenany of said fusible elements are displaced axially,said normally open switch comprising a switch of the microsnap actiontype having a plunger adapted to close the switch upon minute movementthereof, andsaid means coacting with said'switch comprising an armmountedfor'rockingmovement and operable to move said plunger into switchclosing position upon projection of, the fusible element'of anyone ofsaid fuses.

GER'SON'E. WALD.

